The modal class is the class interval with the highest frequency. From the table provided:

• $0 < x \leq 10$: Frequency = 8
• $10 < x \leq 20$: Frequency = 23
• $20 < x \leq 30$: Frequency = 11
• $30 < x \leq 40$: Frequency = 9
• $40 < x \leq 50$: Frequency = 13
• $50 < x \leq 60$: Frequency = 15

The highest frequency is 23, which corresponds to the class interval:

$10 < x \leq 20$

Thus, the modal class is $10 < x \leq 20$.

Would you like more details or explanations?

Related Questions:

1. What is the formula to calculate the mode in a grouped frequency table?
2. How can the mean time spent exercising be calculated from this table?
3. What is the cumulative frequency for $x \leq 30$?
4. How can the range of the data set be determined?
5. What is the importance of identifying the modal class in such data?

Tip:

When analyzing grouped frequency data, identifying the modal class gives a quick sense of where the majority of observations lie. This is especially useful in understanding trends.